T1R1I1H4E1D2R1A1L1S1
14 points
TRIHEDRALS is validvalid
TRIHEDRAL, [n]
TRIHEDRAL, a solid having three sides or faces; thus, a trihedral angle is a solid angle bounded by three plane angles [n]
TRIHEDRAL, [n]
TRIHEDRAL, a solid having three sides or faces; thus, a trihedral angle is a solid angle bounded by three plane angles [n]